retrieveThreadMemberByIdOrNull
suspend fun ThreadChannel.retrieveThreadMemberByIdOrNull(id: Long, useCache: Boolean = true): ThreadMember?(source)
suspend fun ThreadChannel.retrieveThreadMemberByIdOrNull(id: String, useCache: Boolean = true): ThreadMember?(source)
Same as ThreadChannel.retrieveThreadMemberById, but returns null on ErrorResponse.UNKNOWN_MEMBER.